One way to read that data:
opts = detectImportOptions('temperature.xlsx'); %ask matlab to detect the format of the file
opts.VariableTypes{2} = 'duration'; %override format of Time to duraiton
opts = setvaropts(opts, 'Time', 'DurationFormat', 'hh:mm:ss') %display duration as hh:mm:ss
tt = readtimetable('temperature.xlsx', opts)
Excel must do some rounding on the time that matlab doesn't do as some times are off by one second